Electron discharge tube



March 20, 1956 c. E. NEAT 2,739,259

ELECTRON DISCHARGE TUBE Filed April 8, 1952 OUTPUT INVENTOR 0/. neawas E. NEAT,

77flmazflwm 0mm ATTORNEYS,

ELECTRON DISCHARGE TUBE Clarence E. Neat, Gloucester, N. 3.

Application April 8, 1952, Serial No. 281,140

Claims. (Cl. 313-72) This invention relates to electron tubes, and more particularly to an improved electron discharge tube having means for controlling the output anode current through the tube.

The main object of the invention is to provide a novel and improved electron discharge tube which is simple in construction, which is compact in size, and which may be employed either to provide negative or positive transconductance characteristics.

A further object of the invention is to provide an improved electron discharge tube which is relatively inexpensive to manufacture, which is rugged in construction; and which may be employed either to .provide a reduced voltage output, whereby it may be employed for desired purposes such as volume compression or the like, or may be employed to provide an amplified output having a more linear characteristic than is ordinarily available from a conventional triode. v a

A further object of the invention is to provide an improved electron discharge tube which may be employed either as a triode to provide amplified output or as a diode providing similar amplification.

Further objects and advantages of theinvention will become apparent from the following description and claims, and from the accompanying drawings, wherein:

Figure 1 is a horizontal cross'sectional view taken through one form of electron discharge tube constructed in accordance with the present invention.

Figure 2 is a vertical cross sectional view taken through the discharge tube shown in Figure 1 and showing the internal components in side elevation.

Figure 3 is a vertical cross sectional view taken on the line 33 of Figure 1.

Figure 4 is a horizontal cross sectional view of another form of improved discharge tube according to the present invention.

Figure 5 is a side elevational view, partly in vertical cross section of the form of tube shown in Figure 4.

Figure 6 is a vertical cross sectional view taken on the line 6-6 of Figure 4.

Figure 7 is a typical wiring diagram showing the improved electron discharge tube connected as a diode in an electrical circuit.

Figure 8 is a typical wiring diagram illustrating an arrangement wherein the improved electron discharge tube of the present invention is employed as a triode.

Referring to the drawings, and more particularly to Figures 1, 2 and 3, one form of improved electron discharge tube according to the present invention is designated generally at 11. The discharge tube comprises a central axially arranged cathode 12 which may contain a suitable filament, not shown, having leads for connecting same to a source of filament current. The discharge tube 11 is provided with an annular cylindrical outer electrode 13 of sheet metal or the like which is arranged concentrically with respect to the cathode 12, said cathode extending axially of the cylindrical electrode 13. The an- 2,739,259 Patented Mar. 20, 1956 nular electrode 13 is sealed in a drum-shaped casing 14 of glass or other suitable insulating material which forms thehousing for the discharge tube. Connected to the outer electrode 13 is a lead wire 15.

Designated at 16 is the output anode which is cylindrical in shape and which is arranged concentrically with respect to the cathode 12, said output anode 16 being located inwardly adjacent the outer electrode 13, as shown. Designated at 17 is a flat annular control electrode which is arranged concentrically with respect to the cathode 12 and which is located inwardly of the output anode 16 and which is connected thereto by a plurality of radial connecting bars 18. The bottom edge of the output anode 16 is serrated, as shown at 19, and the serrations are directed away from and are offset from the plane of the annular control electrode 17, as is clearly shown in Figure 3. As shown in Figure 3, the apices of the serrations 19 are directed downwardly away from the plane of the control electrode 17, the control electrode being located substantially in the plane of the top rim of the output anode 16.

Designated at 20, 20 are respective focussing electrodes ofannular shape which are supported concentrically around-the cathode 12 between said cathode and the control electrode 17, said focussing electrodes 2%) being supported on their terminal wires 21, and being arranged to define an annular electron fo'cussing slot 22 located substantially in the radial plane of the outputanode 16.

it will be understood that when the cathode 12 is energized and when the anodes 13 and '16 are'con'nected to which is positive relative to said cathode, the electrons will be focussed and will assume the form ofa flat ci1- cular sheet'which is concaved toward 'thecontrol 'elec trode 17 because'of the attraction. exerted by said-control electrode on the electrons, and whose concavity may be varied by varying the magnitude of the positive potential on said control electrode. For example, thedevice may be connected in the manner shown in Figure 7, wherein the cathode 12 is connected to the negative terminal of a battery 23, having an intermediate grounded cell tern1inal, shown at 24. Connected to the positive terminal of the battery 23, shown at 215, is the negative terminal of another battery 26 whose positive terminal is connected by a wire 27 to the terminal lead 15 of the outer anode 13.

The focussing electrodes 20, 24 are connected together, 7

as by an external connection 28 and are connected to ground. Designated at 29 is an input device which may be a transducer, such as a microphone, or other variable resistance device, or alternatively may be a signal source. The input device 29 is connected in series with a load resistor 30 between the common terminal 21 of electrodes 16 and 17 and the positive terminal 25 of battery 23. From the circuit of Figure 7, it will be seen that as the potential on the control anode 17 increases, the electron stream, shown at 31, will be deflectedupwardly as it moves toward the output anode 16 and will be inter cepted by an increasing area of the output anode 16 in view of the triangular shape of the serrations 19. Therefore, a correspondingly increased current will flow in the series circuit including the input device 29 and the load resistor 36, and an amplified potential will appear across properly designing the serrations 19, almost perfect lin-' tive terminal of the'battery'26. The outer-electrode 13' acts as a high voltage anode to attract the saucer shaped' electron beam and to provide ajsufiicient acceleration: on

the electrons of said beam to cause said flat saucer-shaped beam, to pass through the notches in the. output anode 16.-

Referringnow to Figures 4, -and 6, the output anode, shown at 16', may be arranged with the apices of the serrations 1'9 directed upwardly, as ;viewed in Figures; 5

and- 6, namely toward theplane of the=control electrode- 17, whereby increase of potential on the controlelectrode 17'causesa'decrease in the number of electrons intercepted by the output anode 16-, and consequently causes the current flowing in the series circuitcontaining the inputdevice 29 and the load resistor to be reduced in accordance with increases in potential on the control electrode 17. This provides a negative transconductance characteristic, inasmuch as theoutput current in the'circuit containing the load resistor30'is reduced when the resistance of the input device 29 decreases, Where said input device is of the variable resistance type, or where the signal voltage provided by said input device increases, as where the input device is a signal source.- The electron discharge tube of Figures 4,- 5 and 6, may he therefore employed in a circuit, such as shown in Figure 7, toprovide a voltage compression effect, such as the signal compression desired in certain types ofaudio equipment.

The degree of voltage compression, namely, the negative transconductance of theelectron discharge, tubes may be regulated both by. varying the shapeof the serrations 19and by varying the potentials provided by the batteries 23 and26. In the form of the invention shown in Figures 1, 2 and 3, the amplification factor, as. well as the linearity ,of the characteristics of the tube r'nay be-v varied by varying said battery voltages.

Referring now to Figure 8, the device may-be employed.

as a triode by providing separate connectionsfor the control electrode 17 and the output anode 16. Instead;

of employing the radial connection bars'18, as described in the previous forms of the invention, the electrodes 16 and 17 are provided with separate leads extending through the insulating wall of the tube. As shown in Figure 8, the output anode 16 may be connected in series with the load'resist'or 3G and the controlelectrode 17 maybe .con nected between the signal input source 29' and ground. This provides substantially a conventional amplifier triode arrangement wherein the control electrode17 takes the place of the amplifier triode grid and the output anode 16 takes the place ofthe conventional amplifier triodeplate. The device may either be apositive transconductance tube, as shown in Figures 1 to 3, whereby the circuit performs substantially in the same manner as a conventional triode amplifier circuit, or the device may be arranged as shown. in Figures 4, 5 and 6, whereby the said circuit exhibitsa negative transconductance. The circuit of Figure 8, or a similar circuit employing the device of Figures 4, 5

and 6 may be employed to provide signal compressionsimilar to the signal compression provided inthe diodeconnected arrangement of the device illustrated in Figure 7.

While certain specific embodiments of an improved electron discharge device have been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is-intended that no limitations be placed on the invention except as defined by the scope-of the appended claims.

What is' claimed is: j

1. In a vacuum tubeof the character described, a cathode, an annular cylindrical outerelectrodesurround ingandiconcentricwith said cathode, a flat annularcontrol electrodearranged in a radial plane concentric-with plane and having irregular edges arranged so that said ranged concentrically with said cathode between the control electrode and the outer electrode, the major portion of said output anode being spaced axially from said radial output anode will gradually. intercept varying quantities of electrons from the cathode'in accordance with the potential applied to said control electrode, and conductor means electrically connecting theoutput' anode and said control electrode together, said conductor means being arranged so 'that exactly the same; potential exists on said anode and control electrode. 7

2. In a vacuum tube of the character described, a substantially rod-like cathode, an annular cylindrical outer electrode surrounding and concentric with said cathode, a fiat annular control electrode arranged in a radial plane concentric with said cathode. and, located between the cathode; and the outer electrode, an annular focusingv electrode v arranged concentrically with said cathodeand located between said cathode and the control electrode,

an annular cylindrical output anodearranged concentrically with sa-id cathode between the controlelectrode and the outer electrode, the major portion of said output anode being spaced axially fromsaid radial plane and having.

serrated edges, the apices of the. serrations on said edges being directed toward said radial plane. andsaid serrations being arranged so that said output anode will gradually intercept decreasing quantities of electrons from the cathode inaccor'dance, withincreases ,inthe potentialapplied to said'control electrode, and conductor means electrically connecting the output anode andsaid control electrode together saidconductor means being arranged so that eXactly the samepotential existsion said anode and controlelectrode, said focusing electrode being provided with an annular electron focusing slot located substantially 1n the radial plane of. the. output anode.

- 3.- In a vacuum tube of the character described, a cathode, anannular cylindrical outer electrode surrounding and concentricv withsa'id cathode, a flat annular control electrode, arranged concentrically with said, cathode and located between the cathode and the outer electrode, an annular cylindrical output anode arranged concentrically with said cathode between the control electrodeand the outer-'electrode, and means electrically connecting said control electrode and output anode together to place said' control electrode and output anode at the same potential, the major portion of said output anode being spaced axially from said radial plane and having irregular edges and being arranged so that said output anode will gradually intercept varyingv quantities of electrons from the cathode in accordance with the potential applied tosaid-control electrode and output anode.

4. In a vacuum tube ofthe character described, a substantially rod-like cathode, an annular cylindricaljouter electrode surrounding and-concentric with said cathode, a fiat annular control electrode arranged concentrically with said cathode and located between the cathode and the outer electrode an annular focusing electrode arranged concentrically with said cathode and locatedjbetween said cathode and the control eelctrode, an annular cylindricaloutput'anodearranged concentricallywithsaid cathode between the control electrode and the outer electrode,

the major portion of. said output anode being spaced axially from said radial planeand having serrated edges,

and means eiectricallyfconnecting said'c'o'ntr'ol electrode and'said output anode'together .to place said controlelec trode and output anode at the: same potential, said serrated edges being. arranged so that--said, output anode.

will gradually intercept 'varying quantities of" electrons from, the cathode in accordance with the potential applied to said controlelectrode and output anode.

5. In'a vacuumtube ofthecharacter described, a cathode, an annular cylindrical outer electrode surrounding and concentric with saidcathode, a Hat annular control electrode arranged in a" radial plane concentric with said cathode and located between the cathode and the outer electrode, an annular cylindrical output anode arranged concentrically with said cathode between the control electrode and the outer electrode, the major portion of said output anode being spaced axially from said radial plane and having serrated edges, the apices of the serrations on said edges being directed toward said radial plane, and means electrically connecting said control electrode and output anode together to place said control electrode and output anode at the same potential, said serrated edges being arranged so that said output anode will gradually intercept decreasing quantities of electrons from the cathode in accordance with increases in the potential applied to said control electrode and output anode.

References Cited in the file of this patent UNITED I STATES PATENTS Glass Aug. 18, 1953 

